1、Designation: D 4506 08Standard Test Method forDetermining In Situ Modulus of Deformation of Rock MassUsing Radial Jacking Test1This standard is issued under the fixed designation D 4506; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method is used to determine the in situmodulus of deformation of rock mass by subjecting a
3、testchamber of circular cross section to uniformly distributedradial loading; the consequent rock displacements are mea-sured, from which elastic or deformation moduli may becalculated. The anisotropic deformability of the rock can alsobe measured and information on time-dependent deformationmay be
4、obtained.1.2 This test method is based upon the procedures devel-oped by the U.S. Bureau of Reclamation featuring longextensometers (1).2An alternative procedure is also availableand is based on a reference bar (2).1.3 Application of the test results is beyond the scope of thistest method, but may b
5、e an integral part of some testingprograms.1.4 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.5 This standard does not purport to addr
6、ess all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D 653 Terminol
7、ogy Relating to Soil, Rock, and ContainedFluidsD 3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD 4403 Practice for Extensometers Used in Rock3. Terminology3.1 Definitions: See Terminology D 653 fo
8、r general defini-tions.3.2 Definitions of Terms Specific to This Standard:3.2.1 deformationthe change in the diameter of the exca-vation in rock (test chamber).4. Summary of Test Method4.1 A circular test chamber is excavated and a uniformlydistributed pressure is applied to the chamber surfaces bym
9、eans of flat jacks positioned on a reaction frame. Rockdeformation is measured by extensometers placed in boreholesperpendicular to the chamber surfaces. Pressure is measuredwith a standard hydraulic transducer. During the test, thepressure is cycled incrementally and deformation is read ateach incr
10、ement. The modulus is then calculated. To determinetime-dependent behavior, the pressure is held constant anddeformation is observed over time.5. Significance and Use5.1 Using this test method, a volume of rock large enough totake into account the influence of discontinuities on theproperties of the
11、 rock mass is loaded. The test should be usedwhen values are required which represent the true rock massproperties more closely than can be obtained through lessexpensive uniaxial jacking tests or other procedures.NOTE 1The quality of the result produced by this standard isdependent on the competenc
12、e of the personnel performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D 3740 are generally considered capable of competentand objective testing/sampling/inspection/etc. Users of this standard arecautioned that compliance with Practice D
13、 3740 does not in itself assure1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.Current edition approved July 1, 2008. Published July 2008. Originally approvedin 1985. Last previous edition appr
14、oved in 2006 as D 4506 02 (2006).2The boldface numbers in parentheses refer to the list of references appended tothis standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information
15、, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.reliable results. Reliable results depend on many fac
16、tors; Practice D 3740provides a means of evaluating some of those factors.6. Apparatus6.1 Chamber Excavation EquipmentThis includes drillingand “smooth wall” blasting equipment or mechanical excava-tion equipment capable of producing typically a 9-ft (3-m)diameter tunnel with a length about three ti
17、mes that dimension.6.2 Concreting EquipmentConcreting materials andequipment for lining the tunnel, together with strips of weakjointing materials for segmenting the lining.6.3 Reaction FrameThe reaction frame shall be com-prised of steel rings of sufficient strength and rigidity to resistthe force
18、applied by flat jacks, as depicted in Fig. 1. For loadapplication by flat jacks, the frame must be provided withsmooth surfaces; hardwood planks are usually inserted be-tween the flat jacks and the metal rings.6.4 Loading Equipment, to apply a uniformly distributedradial pressure to the inner face o
19、f the concrete lining,including:6.4.1 Hydraulic Pump, with all necessary hoses, connectors,and fluid, capable of applying the required pressure and ofholding this pressure constant to within 5 % over a period of atleast 24 h.6.4.2 Flat Jacks, used for load application (Fig. 1), of apracticable width
20、 and of a length equal at least to the diameterof the tunnel (9 ft (3 m). The jacks should be designed to loadthe maximum of the full circumference of the lining withsufficient separation to allow displacement measurements, andshould have a bursting pressure and travel consistent with theanticipated
21、 loads and displacements. Stainless steel flat jacks ineffective contact with 90 % of the area are recommended, withthe maximum pressure capacity twice the design pressure.1. Measuring profile. 2. Distance equal to the length of active loading. 3. Control extensometer. 4. Pressure gauge. 5. Referenc
22、e beam. 6. Hydraulic pump. 7. Flat jack.8. Hardwood lagging. 9. Shotcrete. 10. Excavation diameter. 11. Measuring diameter. 12. Extensometer drillholes. 13. Dial gauge extensometer. 14. Steel rod. 15.Expansion wedges. 16. Excavation radius. 18. Inscribed Circle. 19. Rockbolt anchor. 20. Steel ring.F
23、IG. 1 Radial Jacking TestD45060826.5 Load Measuring EquipmentLoad measuring equip-ment shall consist of one or more hydraulic pressure gages ortransducers of suitable range, capable of measuring the appliedpressure with an accuracy better than 62 %. Measurements areusually made by means of mechanica
24、l gages. Particular care isrequired to guarantee the reliability of electric transducers andrecording equipment, when used.6.6 Displacement Measuring EquipmentDisplacementmeasuring equipment to monitor rock movements radial to thetunnel must have a precision better than 0.01 mm. Multiple-position (s
25、ix anchor points) extensometers in accordance withPractice D 4403 should be used. The directions of measure-ment should be normal to the axis of the tunnel. Measurementsof movement should be related to reference anchors rigidlysecured in rock, well away from the influence of the loadedzone. The mult
26、iple-position extensometers should have thedeepest anchor as a reference situated at least 3 test-chamberdiameters from the chamber lining.7. Personnel Qualification and Equipment Calibration7.1 All personnel involved in performing the test, includingthe technicians and test supervisor, shall be for
27、mally prequali-fied under the quality assurance procedures established as partof the overall testing program.7.2 The compliance of all equipment and apparatus with theperformance specifications in Section 6 shall be verified.Performance verification is generally done by calibrating theequipment and
28、measurement systems. Calibration and docu-mentation shall be accomplished in accordance with standardquality assurance procedures.8. Procedure8.1 Test Chamber:8.1.1 Select the test chamber location taking into consider-ation the rock conditions, particularly the orientation of therock mass elements
29、such as joints, bedding, and foliation inrelation to the orientation of the proposed tunnel or opening forwhich results are required.8.1.2 Excavate the test chamber by smooth (presplit) blast-ing to the required diameter of 9 ft (3 m), with a length equalto at least three diameters.8.1.3 Record the
30、geology of the chamber and specimenstaken for index testing, as required. Core and log all instru-mentation holes as follows:8.1.3.1 Cored BoreholesDrill the boreholes using dia-mond core techniques. Continuous core shall be obtained.8.1.3.2 Core LoggedCompletely log the recovered core,with emphasis
31、 on fractures and other mechanical nonhomoge-neities.8.1.4 Accurately mark out and drill the extensometer holes,ensuring no interference between loading and measuring sys-tems. Install six-point extensometers and check the equipment.Place two anchors deep beyond the tunnel influence, appropri-ately
32、spacing the other four anchors as close to the surface ofthe tunnel as possible.8.1.5 Assemble the reaction frame and loading equipment.8.1.6 Line the chamber with concrete to fill the spacebetween the frame and the rock.8.2 Loading:8.2.1 Perform the test with at least three loading andunloading cyc
33、les, a higher maximum pressure being applied ateach cycle. Typically, the maximum pressure applied is 1000psi (7 MPa), depending on expected design loads.8.2.2 For each cycle, increase the pressure at an average rateof 100 psi/min (0.7 MPa/min) to the maximum for the cycle,taking not less than 10 in
34、termediate sets of load-displacementreadings in order to define a set of pressure-displacementcurves (see Fig. 2). The automation of data recording isrecommended.8.2.3 On reaching the maximum pressure for the cycle, holdthe pressure constant for 10 min. Complete each cycle byreducing the pressure to
35、 near zero at the same average rate,taking a further three sets of pressure-displacement readings.8.2.4 For the final cycle, hold the maximum pressureconstant for 24 h to evaluate creep. Complete the cycle byunloading in stages, taking readings of pressure and corre-sponding displacements similar to
36、 the loading cycle.9. Calculation9.1 Correct the applied load values to give an equivalentdistributed pressure, p1, on the test chamber lining, as follows:p15(b2pr1pm(1)where:p1= distributed pressure on the lining at r1, psi (MPa),r1= radius, ft (m),pm= pressure in the flat jacks, psi (MPa), andb =
37、flat jack width (see Fig. 3), ft (m).9.1.1 Calculate the equivalent pressure p2at a “measuringradius” r2just beneath the lining; this radius being outside thezone of irregular stresses beneath the flat jacks and the liningand loose rock (see Fig. 3).P25r1r2P15(b2p r2Pm(2)Pm(b 5 P12r1 pP15Pm(b2p r1P2
38、5 P1r1r29.2 Superposition is only strictly valid for elastic deforma-tions but also gives a good approximation if the rock isFIG. 2 Typical Graph of Applied Pressure Versus DisplacementD4506083moderately plastic in its behavior. Superposition of displace-ments for two fictitious loaded lengths is us
39、ed to give theequivalent displacements for an “infinitely long test chamber.”This superposition is made necessary by the comparativelyshort length of the test chamber in relation to its diameter.9.3 Plot the result of the long duration test, Ddundermaximum pressure, max P2, on the displacement graph
40、 (Fig.4). Proportionally correct test data for each cycle to give thecomplete long-term pressure-displacement curve. The elasticcomponent, De, and the plastic component, Dp, of the totaldeformation, Dt, are obtained from the deformation at the finalunloading:Dt5Dp1Desee Fig.4! (3)9.4 The elastic mod
41、ulus, E, and the deformation modulus,D, are obtained from the pressure-displacement graph (Fig. 2)using the following formulae based on the theory of elasticity:E 5p2r2De1 1n!n(4)D 5p2r2Dt1 1n!nwhere:p2= maximum test pressure, andn = estimated value for Poissons Ratio.9.4.1 As an alternative to 9.4,
42、 the moduli of undisturbedrock may be obtained, taking into account the effect of afissured and loosened region, by using the following formulae:E 5p2r2DeSn11n1 lnr3r2D(5)D 5p2r2DtSn11n1 lnr3r2Dwhere:r3= radius to the limit of the assumed fissured andloosened zone, ft (m), andln = natural logarithm.
43、9.4.2 AssumptionsThis solution is given for the case of asingle measuring circle with extensometer anchors immedi-ately behind the lining. The solution assumes linear-elasticbehavior for the rock and is usually adequate in practice,although it is possible to analyze more complex test configu-rations
44、 (using, for example, a finite element analysis).10. Report10.1 The purpose of this section is to establish the minimumrequirements for a complete and usable report. Further detailsmay be added as appropriate, and the order of items may bechanged. If application of the test results is part of the te
45、stingprogram, an application section compatible with the formatdescribed below should be included. The report shall includethe following:10.1.1 Introductory SectionThe introductory section isintended to present the scope and purpose of the testingprogram and the characteristics of the material teste
46、d, asfollows:10.1.1.1 ScopeThis shall include (1) the location andorientation of the test boreholes (a graphic presentation isrecommended), (2) the reasons for selecting the test locations,and (3) in general terms, a discussion of the limitations of thetesting program, that is, the areas of interest
47、 not covered by thetesting program and the limitations of the data within the areasof application.10.1.2 Brief Description of the Test Site GeologyDescribethe rock type macroscopically from both field inspection andfrom the core logs of the test boreholes. Discuss structuralfeatures affecting the te
48、sting, as appropriate. Include a listing ofthe types of data available on properties of the rock corescontaining such property data as may aid interpretation of theFIG. 3 Scheme of Loading Showing Symbols Used in theCalculationsFIG. 4 Typical Graph Showing Total and Plastic Displacements asa Functio
49、n of Direction Perpendicular to the Test Chamber AxisD4506084test data (for example, rock quality designation (RQD), labo-ratory tests of strength and deformation).10.1.3 Test Method Section:10.1.3.1 Equipment and ApparatusInclude a detailed list-ing of the equipment actually used for the test. The name,model number, and basic specifications of each major pieceshall be presented in the report.10.1.3.2 ProcedureList in detailed steps the procedureactually used for the test.10.1.3.3 VariationsIf the actual equipment or procedurehas varied fro
